Pumping equipment



Jan. 6, 1942. V "w. J. CRITE'S- 2,268,701

PUMPING EQUIPMENT Filed Sept. 18, 1939 INVENTOR 4 v w. J. CRITES f BY L Li Patented Jan. 6, 1942 PUMPING EQUIPMENT Qilbur J. Orites, Bartlesville, kla'., assignor to Phillips Petroleum Company, a corporationoot Delaware Application September 18,1939, Serial No. 295,523

1 Claim. (01. 74-41) This invention relates to improvements in,

pumpingmachinery used in the production of oil from wells, and particularly, to the equipment employingan electric motor as a prime mover of such machinery.

In pumping oil from wells it is the most common practice to employ what is known as the sucker rod type of pump. These pumps have a piston disposed in a pump barrel at the lower end of the well, and a string of sucker rods extending upwardly 'to a reciprocating device at the upper end of the well. In pumping deep wells, the weight of the rod string is of considerable magnitude and as aconsequence, must be counter-balanced by a number of weights on the reciprocating pumping equipment at the upand of the well; Counter-balancing in this manner tends to balance the load on the driving motor and decrease the variation between the amount of power required in lowering the rod string and the amount 01' power required to raise the rod string together with the oil being pumped. Two factors which prevent an even power requirement during the entire cycle of raising and lowering are the elasticity of the rodsand the compressibility of the fluid produced by the well. 'As'a consequence, power.

requirements during one cycle of the pumping of a deep well vary over a wide range despite the efiect of counterbalancing.

In the application of electric motors to the pumping of beam operated wells, it has been an accepted practice to install electric motors 01' a rated power capacity fli'ty percent in excess of the power required to pump the well by a gas engine loaded to its full capacity. Attempts were made to install electric motors of the same rated power capacity as was, required when using gas engines, with the result that the electric motors showed excessive heating and other symptoms of being overloaded. In making an synchronous speed. Any energy imparted to the motor by the pumping unit was not stored up in the motor itself, but was converted into electrical energy-and dissipated through the power transmission lines. In analyzing the characterist-ics'of a gas engine application to the pumping 'unit, it was found that energy imparted to the gas engine by the pumping unit was converted into kinetic energy of the flywheel and was stored as kinetic energy within the flywheel until needed during;the peak load on the pumping equipment.

The present invention proposes to apply a flywheel to an electric motor installation to store up kinetic energy during periods of slack loads on the pumping equipment and to utilize this energyduring peak 1oads on the pumping equipv merit to assist, the motor in carrying over. the peak loads without overloading the motor. The application of a flywheel to electric motor driven well pumping equipment was successfully carried out in an installation in an oil field in the State of Arkansas. It was found preierable to use a flexible coupling between the flywheel and the pumping equipment to prevent shock loading on the pumping equipment and the driving .motor during the peak load period. Application ,of a flywheel in this manner has proven successful in these pumping operations and has repacity of the electric motor installed may be equivalent to the rated power capacity of a gas engine required to pump the same well. This means a decrease in rated motor power capacity of aboutthirty percent over the usual practice in installing electric motors which in turn means a decrease of about fifty percent in the cost of the electric motor used. The increased cost due to thegflywheel and flexible coupling is negligiblein comparison to the decrease in the cost of the electric motor used.

Decreased operating expenses. Operating "expenses are decreased since the motor is not overloaded and therefore not subject to excessive current consumption or overheating. Actual operation in the Arkansas fleld showed that the application of a flywheel and flexible coupling to an electric 'moton installation eflected an overall efliciency increase of two and one-half percent and reduced the operating temperature of the motor thirteen degrees. This means a longer life for the motor as well as a saving in pumpingequipment during peak loads through the flexible coupling means which protects the equipment from shock loads, increasing the life of the equipment and especially the life of the sucker'rods which are liable to fatigue failure.

An object of this invention is to provide pumping equipment for oil wells which may be efllciently driven by an electric motor. v

A further object of the present invention is the application of a flywheel to pumping equipment to assist the prime mover over periods of peak loads.

A still further object of the present invention is to provide a flywheel and flexible coupling means to pumping equipment to reduce stresses In the drawing where like numerals designate similar parts, the numeral 4 represents the prime mover of a pumping unit for which I prefer to use an electric motor of high slip characteristics. Rotary motion developed by motor 4 is transmitted by shaft 5 to a flywheel 6 and to one-half of a coupling means I connected thereto. A pulley 8 is connected to the other half of coupling means I which is so constructed and arranged as to allow a pre-determined amountof slippage or flexibility between pulley 8 and shaft 5. V- belts S-transmit power from shaft 5 to drive wheel II) which is connected to pitman i l. Pitshaft 5.

man II is connected at one end to the walking beam I2 which is supported by the Samson post ii.

In operation, the prime mover 4 is set in motion and its motion transmitted through shaft I, coupling means I, pulley 8, and belts l to drive wheel it to which the pitman ii is attached. The pitman actuates walking beam i2 and reciprocates the polished rod in the well to effect pumping of oil from the well. Flywheel 8 is set in motion by'prime mover 4 through means of Kinetic energy stored in the flywheel during slack periods is utilized during peak load periods to assist the motor. Shock to the pumping equipment during peak load periods is prevented by the flexible coupling between shaft I and pulley 8.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and

that various changes in the shape, size, and ar-' rangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claim.

Having thus described my invention, I claim:

In a well pumping unit the combination comprising a walking beam having sucker rods attached to one end thereof and a pitman to the other end, a prime mover to drive the pumping means, a flexible hydraulic coupling between the pitman and the prime mover to absorb impact shocks from the sucker rods, and a flywheel connected to the prime mover to store up energy in the flywheel, said energy being imparted to the flywheel by the downward movement of the sucker r'ods.

WILBUR J. CRITES. 

